1. Field of the Invention
The invention pertains to a hydrodynamic clutch arrangement having a pump wheel and a turbine wheel which form a hydrodynamic circuit in a clutch housing. The housing has a drive-side wall connected to a drive unit such as an internal combustion engine, and a clutch device is provided to bring the housing into and out of working connection with the pump wheel.
2. Description of the Related Art
A hydrodynamic clutch arrangement of this type is known from U.S. Pat. No. 6,019,202. It consists of a hydrodynamic torque converter equipped with a pump wheel, a turbine wheel, and a stator to form a hydrodynamic circuit inside a clutch housing. The drive-side housing wall of this clutch housing, i.e., the side of the housing which faces the drive unit, which can be an internal combustion engine, is connected to the drive unit, whereas the takeoff side, i.e., the side facing a gearbox, accepts a clutch device, which makes or breaks the working connection between the clutch housing and the pump wheel.
When equipped with a clutch device such as this, the hydrodynamic clutch arrangement becomes especially suitable for use in machines such as dredging shovels, because these machines require a combination of both traveling and lifting movements, the lifting movement pertaining to the shovel. Thus, by the at least partial disengagement of the clutch device, the transmission of the torque introduced by the drive unit to the pump wheel and thus to the hydrodynamic circuit can be reduced, so that only a residual torque leaves the hydrodynamic clutch arrangement on the takeoff side and is transmitted to the following gearbox. The result is that only a minimal amount of torque is available for the machine's travel, whereas most of the torque supplied by the drive unit can be made available to any desired branching point which allows the shovel to be lifted. Under these operating conditions, it is obvious that the bridging clutch, which is provided as part of the object of the US patent and which is mounted between the clutch housing and the turbine wheel, is released to prevent the torque supplied by the drive unit from being transmitted to the gearbox.
If, however, there is no need to lift the shovel and the main goal is to drive the machine, the clutch device is engaged, so that the torque which has been introduced into the clutch housing, as is conventional practice in hydrodynamic torque converters, can be transmitted either via the hydrodynamic circuit or via the bridging clutch to the gearbox.
U.S. Pat. No. 6,019,202 does not disclose the design of the clutch device, but the drawings allow the conclusion that, although the clutch device acts between the clutch housing and the pump wheel, it is not integrated into the clutch housing. As can also be seen in FIG. 1 of this patent, a separate hydraulic pressure circuit for engaging and disengaging the clutch device must be provided. As a result, the hydrodynamic clutch arrangement becomes complicated in design and also inefficient with respect to energy consumption. In addition, it must be assumed that the arrangement will occupy more than a little space, which should be avoided, even in the case of heavy machines.